The role of pulmonary function in patients with heart failure and preserved ejection fraction: Looking beyond chronic obstructive pulmonary disease

Subclinical impairment of the left atrium is associated with MRI-based lung volume but not with parameters from pulmonary function testing

Left atrial (LA) physiology and hemodynamics are intimately connected to cardiac and lung function in health and disease. This study examined the relationship between MRI-based left atrial (LA) size and function with MRI-based lung volume and pulmonary function testing (PFT) parameters in the population-based KORA study cohort of 400 participants without overt cardiovascular disease. MRI quantification assessed LA size/function in sequences with and without ECG synchronization, alongside lung volume. Regression analysis explored the relationship of LA with MRI lung volume and PFT parameters. Among 378 participants (average age 56.3 ± 9.2 years; 42.3% women), non-gated LA size averaged 16.8 cm2, while maximal and minimal LA size from gated measurements were 19.6 cm2 and 11.9 cm2 respectively. The average MRI-derived lung volume was 4.0 L, with PFT showing a total lung capacity of 6.2 L, residual lung volume of 2.1 L, and forced vital capacity of 4.1 L. Multivariate regression analysis, adjusted for age, gender, and cardiovascular risk factors, revealed an inverse association between maximum LA size, non-gated LA, and LA area fraction with lung volume (ß = - 0.03, p = 0.006; ß = - 0.03, p = 0.021; ß = - 0.01, p = 0.012), with no significant association with PFT parameters. This suggests that MRI-based assessment may offer greater sensitivity in detecting subclinical LA impairment than PFT.

Heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF) accounts for nearly half of all heart failure cases and has a prevalence that is expected to rise with the growing ageing population. HFpEF is associated with significant morbidity and mortality. Specific HFpEF risk factors include age, diabetes, hypertension, obesity and atrial fibrillation. Haemodynamic contributions to HFpEF include changes in left ventricular structure, diastolic and systolic dysfunction, left atrial myopathy, pulmonary hypertension, right ventricular dysfunction, chronotropic incompetence, and vascular dysfunction. Inflammation, fibrosis, impaired nitric oxide signalling, sarcomere dysfunction, and mitochondrial and metabolic defects contribute to the cellular and molecular changes observed in HFpEF. HFpEF impacts multiple organ systems beyond the heart, including the skeletal muscle, peripheral vasculature, lungs, kidneys and brain. The diagnosis of HFpEF can be made in individuals with signs and symptoms of heart failure with abnormality in natriuretic peptide levels or evidence of cardiopulmonary congestion, facilitated by the use of HFpEF risk scores and additional imaging and testing with the exclusion of HFpEF mimics. Management includes initiation of guideline-directed medical therapy and management of comorbidities. Given the significant impact of HFpEF on quality of life, future research efforts should include a particular focus on how patients can live better with this disease.

Cardiopulmonary Exercise Testing in Heart Failure With Preserved Ejection Fraction: Technique Principles, Current Evidence, and Future Perspectives

Heart failure with preserved ejection fraction (HFpEF) is a multifactorial clinical syndrome involving a rather complex pathophysiologic substrate and quite a challenging diagnosis. Exercise intolerance is a major feature of HFpEF, and in many cases, diagnosis is suspected in subjects presenting with exertional dyspnea. Cardiopulmonary exercise testing (CPET) is a noninvasive, dynamic technique that provides an integrative evaluation of cardiovascular, pulmonary, hematopoietic, neuropsychological, and metabolic functions during maximal or submaximal exercise. The assessment is based on the principle that system failure typically occurs when the system is under stress, and thus, CPET is currently considered to be the gold standard for identifying exercise intolerance, allowing the differential diagnosis of underlying causes. CPET is used in observational studies and clinical trials in HFpEF; however, in most cases, only a few from a wide variety of CPET parameters are examined, while the technique is largely underused in everyday cardiology practice. This article discusses the basic principles and methodology of CPET and studies that utilized CPET in patients with HFpEF, in an effort to increase awareness of CPET capabilities among practicing cardiologists.

Association between spirometry pattern, left ventricular diastolic function, and mortality

BACKGROUND

Spirometric abnormalities have been related to incident heart failure in general population, who generally have preserved left ventricular ejection fraction (LVEF). We aimed to investigate the association between spirometric indices, cardiac functions and clinical outcomes.

METHODS

Subjects presenting with exertional dyspnoea and received spirometry and echocardiography were eligible for this study. Forced vital capacity (FVC) and forced expiratory volume in the first second (FEV1)/FVC ratio were measured to define the spirometry patterns: normal (FEV1/FVC ≥ 70%, FVC ≥ 80%), obstructive (FEV1/FVC < 70%, FVC ≥ 80%), restrictive pattern (FEV1/FVC ≥ 70%, FVC < 80%) and mixed (FEV1/FVC < 70%, FVC < 80%). The diastolic dysfunction index (DDi) was the counts of the indicators, including septal e' velocity <7 cm/s, septal E/e' > 15, pulmonary artery systolic pressure > 35 mmHg and left atrial dimension >40 mm.

RESULTS

Among a total of 8669 participants (65.8 ± 16.3 years, 56% men), 3739 (43.1%), 829 (9.6%), 3050 (35.2%) and 1051 (12.1%) had normal, obstructive, restrictive and mixed spirometry pattern, respectively. Subjects with restrictive or mixed spirometry pattern had higher DDi and worse long-term survival than those with obstructive or normal ventilation. FVC but not FEV1/FVC was predictive of 5-year mortality, independent of age, sex, renal function, LVEF, DDi, body mass index, and comorbidities (hazard ratio, 95% confidence intervals: .981, .977-.985). Furthermore, there was an inverse nonlinear relationship between FVC and DDi, suggesting the declined FVC may mediate 43% of the prognostic hazard of left ventricular diastolic dysfunction.

CONCLUSIONS

The restrictive spirometry pattern or the declined FVC was associated with left ventricular diastolic dysfunction, which aggravated the long-term mortality in the ambulatory dyspnoeic subjects.

Higher Work of Breathing During Exercise in Heart Failure With Preserved Ejection Fraction

BACKGROUND

It is unknown if pulmonary alterations in heart failure with preserved ejection fraction (HFpEF) impact respiratory mechanics during exercise.

RESEARCH QUESTION

Are the operating lung volumes, work of breathing (Wb), and power of breathing (Pb) abnormal in patients with HFpEF during exercise?

STUDY DESIGN AND METHODS

Patients with HFpEF (n = 8; median age, 71 years [interquartile range (IQR), 66-80 years]) and control participants (n = 9; median age, 68 years [IQR, 64-74 years]) performed incremental cycling to volitional exhaustion. Esophageal pressure, end-expiratory lung volume (EELV), inspiratory lung volume (EILV), and ventilatory variables were compared at similar absolute (30 and 50 L/min) and relative (45% of peak, 70% of peak, and 100% of peak) minute ventilation (V.E) during exercise.

RESULTS

During exercise, EELVs were not different between patients with HFpEF and control participants (P > .13 for all). EILVs were lower in patients with HFpEF than control participants at 45% and 70% V.E peak (P < .03 for all). Dynamic lung compliance was lower in patients with HFpEF than control participants at 30 L/min, 50 L/min, 45% V.E peak, and 100% V.E peak (P < .04 for all). Compared with control participants, patients with HFpEF showed higher total Wb and Pb at 30 L/min (Wb: median, 1.08 J/L [IQR, 0.93-1.82 J/L] vs 0.52 J/L [IQR, 0.43-0.71 J/L]; Pb: median, 36 J/min [IQR, 30-59 J/min] vs 17 J/min [IQR, 11-23 J/min] and 50 L/min; Wb: median, 1.40 J/L [IQR, 1.27-1.68 J/L] vs 0.90 J/L [IQR, 0.74-1.05 J/L]; Pb: median, 73 J/min [IQR, 60-83 J/min] vs 45 J/min [IQR, 33-63 J/min]; P < .01 for all). At 30 and 50 L/min, inspiratory and expiratory resistive Wb and Pb were higher in patients with HFpEF than control participants (P < .04 for all). Total Wb was higher for patients with HFpEF than control participants at 45% of V.E peak (P = .02). Total Pb was higher for control participants than patients with HFpEF at 100% V.E peak because of higher inspiratory resistive Pb (P < .04 for both).

INTERPRETATION

These data demonstrate the HFpEF syndrome is associated with pulmonary alterations eliciting a greater Pb during exercise resulting from greater inspiratory and expiratory resistive Pb.

Challenging the Hemodynamic Hypothesis in Heart Failure With Preserved Ejection Fraction: Is Exercise Capacity Limited by Elevated Pulmonary Capillary Wedge Pressure?

BACKGROUND

Exercise intolerance is a defining characteristic of heart failure with preserved ejection fraction (HFpEF). A marked rise in pulmonary capillary wedge pressure (PCWP) during exertion is pathognomonic for HFpEF and is thought to be a key cause of exercise intolerance. If true, acutely lowering PCWP should improve exercise capacity. To test this hypothesis, we evaluated peak exercise capacity with and without nitroglycerin to acutely lower PCWP during exercise in patients with HFpEF.

METHODS

Thirty patients with HFpEF (70±6 years of age; 63% female) underwent 2 bouts of upright, seated cycle exercise dosed with sublingual nitroglycerin or placebo control every 15 minutes in a single-blind, randomized, crossover design. PCWP (right heart catheterization), oxygen uptake (breath × breath gas exchange), and cardiac output (direct Fick) were assessed at rest, 20 Watts (W), and peak exercise during both placebo and nitroglycerin conditions.

RESULTS

PCWP increased from 8±4 to 35±9 mm Hg from rest to peak exercise with placebo. With nitroglycerin, there was a graded decrease in PCWP compared with placebo at rest (-1±2 mm Hg), 20W (-5±5 mm Hg), and peak exercise (-7±6 mm Hg; drug × exercise stage P=0.004). Nitroglycerin did not affect oxygen uptake at rest, 20W, or peak (placebo, 1.34±0.48 versus nitroglycerin, 1.32±0.46 L/min; drug × exercise P=0.984). Compared with placebo, nitroglycerin lowered stroke volume at rest (-8±13 mL) and 20W (-7±11 mL), but not peak exercise (0±10 mL).

CONCLUSIONS

Sublingual nitroglycerin lowered PCWP during submaximal and maximal exercise. Despite reduction in PCWP, peak oxygen uptake was not changed. These results suggest that acute reductions in PCWP are insufficient to improve exercise capacity, and further argue that high PCWP during exercise is not by itself a limiting factor for exercise performance in patients with HFpEF.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT04068844.

Defining the Phenotypes for Heart Failure With Preserved Ejection Fraction

PURPOSE OF REVIEW

Heart failure with preserved ejection fraction (HFpEF) imposes a significant burden on society and healthcare. The lack in efficacious therapies is likely due to the significant heterogeneity of HFpEF. In this review, we define various phenotypes based on underlying comorbidities or etiologies, discuss phenotypes arrived at by novel methods, and explore therapeutic targets.

RECENT FINDINGS

A few studies have used machine learning methods to uncover sub-phenotypes within HFpEF in an unbiased manner based on clinical features, echocardiographic findings, and biomarker levels. We synthesized the literature and propose three broad phenotypes: (1) young, with few comorbidities, usually obese and with low natriuretic peptide levels, (2) obese with substantive cardiometabolic burden and comorbidities and impaired ventricular relaxation, (3) old, multimorbid, with high rates of atrial fibrillation, renal and coronary artery disease, chronic obstructive pulmonary disease, and left ventricular hypertrophy. We also propose potential therapeutic strategies for these phenotypes.

Combustion-Derived Particulate PAHs Associated with Small Airway Dysfunction in Elderly Patients with COPD

Evidence of the respiratory effects of ambient organic aerosols (e.g., polycyclic aromatic hydrocarbons, PAHs) among patients with chronic diseases is limited. We aimed to assess whether exposure to ambient particle-bound PAHs could worsen small airway functions in patients with chronic obstructive pulmonary disease (COPD) and elucidate the underlying mechanisms involved. Forty-five COPD patients were recruited with four repeated visits in 2014-2015 in Beijing, China. Parameters of pulmonary function and pulmonary/systemic inflammation and oxidative stress were measured at each visit. Linear mixed-effect models were performed to evaluate the associations between PAHs and measurements. In this study, participants experienced an average PAH level of 61.7 ng/m³. Interquartile range increases in exposure to particulate PAHs at prior up to 7 days were associated with reduced small airway functions, namely, decreases of 17.7-35.5% in forced maximal mid-expiratory flow. Higher levels of particulate PAHs were also associated with heightened lung injury and inflammation and oxidative stress. Stronger overall effects were found for PAHs from traffic emissions and coal burning. Exposure to ambient particulate PAHs was capable of impairing small airway functions in elderly patients with COPD, potentially via inflammation and oxidative stress. These findings highlight the importance of control efforts on organic particulate matter from fossil fuel combustion emissions.

Prognostic Role of Pulmonary Function in Patients With Heart Failure With Reduced Ejection Fraction

Background

Both ventilatory abnormalities and pulmonary hypertension (PH) are frequently observed in patients with heart failure with reduced ejection fraction. We aim to investigate the association between ventilatory abnormalities and PH in heart failure with reduced ejection fraction, as well as their prognostic impacts.

Methods and Results

A total of 440 ambulatory patients (age, 66.2±15.8 years; 77% men) with left ventricular ejection fraction ≤40% who underwent comprehensive echocardiography and spirometry were enrolled. Total lung capacity, forced vital capacity, and forced expiratory volume in the first second were obtained. Pulmonary arterial systolic pressure was estimated. PH was defined as a pulmonary arterial systolic pressure of >50 mm Hg. The primary end point was all‐cause mortality at 5 years. Patients with PH had significantly reduced total lung capacity, forced vital capacity, and forced expiratory volume in the first second. During a median follow‐up of 25.9 months, there were 111 deaths. After accounting for age, sex, body mass index, renal function, smoking, left ventricular ejection fraction, and functional capacity, total lung capacity (hazard ratio [HR] per 1 SD, 0.66; 95% CI per 1 SD, 0.46–0.96), forced vital capacity (HR per 1 SD, 0.64; 95% CI per 1 SD, 0.48–0.84), and forced expiratory volume in the first second (HR per 1 SD, 0.72; 95% CI per 1 SD, 0.53–0.98) were all significantly correlated with mortality in patients without PH. Kaplan‐Meier curve demonstrated impaired pulmonary function, defined as forced expiratory volume in the first second ≤58% of predicted or forced vital capacity ≤65% of predicted, was associated with higher mortality in patients without PH (HR, 2.85; 95% CI, 1.66–4.89), but not in patients with PH (HR, 1.05; 95% CI, 0.61–1.82).

Conclusions

Ventilatory abnormality was more prevalent in patients with heart failure with reduced ejection fraction with PH than those without. However, such ventilatory defects were related to long‐term survival only in patients without PH, regardless of their functional status.

[Chronic obstructive pulmonary disease, sleep-disordered breathing and hypoventilation-Influence on the cardiorenal system]

Comorbidities are frequently observed in patients suffering from pulmonary diseases due to shared risk factors and intricate interactions between various organ systems. This article aims to characterize the effects of selected diseases of the respiratory system on the cardiovascular system and kidneys. Advanced chronic obstructive pulmonary disease (COPD) often leads to a prognostically unfavorable increased pressure in the pulmonary circulation. In this respect treatment of these patients is primarily aimed at the underlying pulmonary disease and targeted treatment of the pulmonary hypertension should only be carried out according to invasive diagnostics and in an individualized manner. So far, the fact that there is a substantial overlap between COPD and heart failure with preserved ejection fraction has been completely ignored, which should be considered in the diagnostic procedure. Obstructive sleep apnea (OSA) has several unfavorable effects on the cardiovascular system and has been identified as an independent risk factor for cardiovascular diseases. The established treatment of OSA with continuous positive airway pressure (CPAP) has been shown to improve daytime sleepiness and the quality of life; however, an effect of CPAP on the occurrence of cardiovascular events, especially in asymptomatic patients, has so far not been demonstrated in randomized trials. Peripheral edema is frequently observed in patients suffering from chronic hypercapnia, which can be explained by several pathophysiological mechanisms, including pulmonary vasoconstriction and a direct effect of the hypercapnia on renal blood flow. Apart from the administration of diuretics, recompensation of such patients always requires treatment of the hypercapnia by noninvasive ventilation.

FEV1 Predicts Cardiac Status and Outcome in Chronic Heart Failure

BACKGROUND

COPD is an established predictor of clinical outcome in patients with chronic heart failure (HF). However, little evidence is available about the predictive value of FEV₁ in chronic HF.

RESEARCH QUESTION

Is pulmonary function related to the progression of chronic HF?

STUDY DESIGN AND METHODS

The MyoVasc study (ClinicalTrials.gov Identifier: NCT04064450) is a prospective cohort study of HF. Information on pulmonary and cardiac functional and structural status was obtained by body plethysmography and echocardiography. The primary study end point was worsening of HF.

RESULTS

Overall 2,998 participants (age range, 35-84 years) with available FEV₁ data were eligible for analysis. Linear multivariate regression analysis revealed an independent relationship of FEV₁ (per -1 SD) with deteriorated systolic and diastolic left ventricle (LV) function as well as LV hypertrophy under adjustment of age, sex, height, cardiovascular risk factors (CVRFs), and clinical profile (LV ejection fraction: β-estimate, -1.63% [95% CI, -2.00% to -1.26%]; E/E' ratio: β-estimate, 0.82 [95% CI, 0.64-0.99]; and LV mass/height^2.7: β-estimate, 1.58 [95% CI, 1.07-2.10]; P < .001 for all). During a median time to follow-up of 2.6 years (interquartile range, 1.1-4.1 years), worsening of HF occurred in 235 individuals. In Cox regression model adjusted for age, sex, height, CVRF, and clinical profile, pulmonary function (FEV₁ per -1 SD) was an independent predictor of worsening of HF (hazard ratio [HR], 1.44 [95% CI, 1.27-1.63]; P < .001). Additional adjustment for obstructive airway pattern and C-reactive protein mitigated, but did not substantially alter, the results underlining the robustness of the observed effect (HR_FEV1, 1.39 [95% CI, 1.20-1.61]; P < .001). The predictive value of FEV₁ was consistent across subgroups, including individuals without obstruction (HR, 1.55 [95% CI, 1.34-1.77]; P < .001) and nonsmokers (HR, 1.72 [95% CI, 1.39-1.96]; P < .001).

INTERPRETATION

FEV₁ represents a strong candidate to improve future risk stratification and prevention strategies in individuals with chronic, stable HF.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT04064450; URL: www.clinicaltrials.gov.

Measuring pulmonary function in COPD using quantitative chest computed tomography analysis

COPD is diagnosed and evaluated by pulmonary function testing (PFT). Chest computed tomography (CT) primarily serves a descriptive role for diagnosis and severity evaluation. CT densitometry-based emphysema quantification and lobar fissure integrity assessment are most commonly used, mainly for lung volume reduction purposes and scientific efforts.

A shift towards a more quantitative role for CT to assess pulmonary function is a logical next step, since more, currently underutilised, information is present in CT images. For instance, lung volumes such as residual volume and total lung capacity can be extracted from CT; these are strongly correlated to lung volumes measured by PFT.

This review assesses the current evidence for use of quantitative CT as a proxy for PFT in COPD and discusses challenges in the movement towards CT as a more quantitative modality in COPD diagnosis and evaluation. To better understand the relevance of the traditional PFT measurements and the role CT might play in the replacement of these parameters, COPD pathology and traditional PFT measurements are discussed.

CT may be used as a proxy for lung function in COPD diagnosis and evaluation, particularly for the hyperinflation markershttps://bit.ly/2RrGAZf

Epidemiological and clinical boundaries of heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF) is highly prevalent and is associated with relevant morbidity and mortality. However, an evidence-based treatment is still absent. The heterogeneous definitions, differences in aetiology/pathophysiology, and diagnostic challenges of HFpEF made it difficult to define its epidemiological landmarks so far. Several large registries and observational studies have recently disclosed an increasing incidence/prevalence, as well as its prognostic significance. An accurate definition of HFpEF epidemiological boundaries and phenotypes is mandatory to develop novel effective and rational therapeutic approaches.